Liz Braun, QMI Agency

The diminutive actor is fast and funny and intense in person, fully engaged and engaging at all times.

You could describe his conversational style as spellbinding.

Radcliffe, 25, visited Toronto to promote The F Word (a film also known as What If), a romantic comedy that investigates the issue of falling in love with your best friend. It opens here Friday.

Radcliffe stars opposite Zoe Kazan; their on-screen chemistry is wonderful, and so is Elan Mastai's script. The F Word was directed by Michael Dowse, who did FUBAR and Goon, so it should be said that this is romance with an edge — and not a chick flick.

"What I really did enjoy in this film was being able to play a modern human being," Radcliffe says of The F Word. "I'd never played anyone contemporary before. Harry Potter was sort of contemporary, but also so in its own world that it didn't feel natural or grounded in reality.

“It was lovely being able to wear stuff I might wear, and speak sort of normally."

In fact, says Radcliffe, there's a bit of who he really is in Wallace, his F Word character. The dialogue is often hilarious, and he says, "My own sense of humour and Zoe's were allowed to come out. One of the things that interested me about Wallace is that we shared a sense of humour. I share a lot of sensibilities with the character."

Radcliffe refers to an early scene in which he and Kazan discuss the pronunciation of a word. "You know when he goes on a rant about how to pronounce 'forte'? Um — I'm kind of that guy, who would pick you up on some etymology at a party." He laughs, but looks slightly embarrassed. "I'm completely pedantic. I've always been fascinated with words. It is terrible, because when somebody misuses a word or uses a double negative or anything like that, it's like a f-----g knife in my ear. I'm like, 'AGGGH! No!'" He laughs again. "I should have been a word snob in the 1800s."

The F Word, which is set in Toronto, was one of three movies Radcliffe had at TIFF in 2013. The others included the dark fantasy-thriller Horns (also filmed in Canada) and the period drama Kill Your Darlings, in which he plays the young Allen Ginsberg. (Radcliffe won't be at TIFF this year, although it's tempting — he wants to see Erin Darke in the Brian Wilson biopic that will be at the festival. "Go and see Love & Mercy," he advises. "My girlfriend did that." Duly noted.)

Along with the critically well-received Woman In Black, these films are Radcliffe's post-Potter body of work. Next up will be Frankenstein, in which he plays the lab assistant, Igor, to James McAvoy's Dr. Frankenstein.

"I'm very intrigued to see that film. I made some bold choices, physically. I don't know if they'll come off," he says with a laugh.

"It was similar to doing Horns. I got to the end and thought, 'That's a reeeeally weird movie I just did and I don't know how it's going to turn out!'"

Certainly, Radcliffe has made the transition from boy wonder to adult actor look easy.

"I'd never thought about the possibility of failing to make a career for myself and not being an actor anymore, before people came in and started asking me about it," he says. "I was asked by one person, 'Do you feel your best years are behind you?' At 20? I didn't until you asked me!"

Crediting his parents and the people who watched over him and guided him on set when he was a child actor, Radcliffe says, "There was a part of me that wanted to do it for them, to be sure I carved out a career for myself because of all these people I've worked with and how hard they've worked with me."

He also wanted to disprove the notion that being a child actor is always horrible. "It gave me such confidence, being on set, and it gave me a sense of community and the importance of team work."

Radcliffe says he thinks it's a much tougher slog to be a child actor in America, and particularly in Hollywood.

"The instinct to lambaste people who've fallen off the rails is so weird. People talk about child actors and celebrities going off the rails like it's f-----g sport."

He adds, "I'm lucky to have the parents I have and an incredibly stable family background, which not everyone has. That and the people I had on set — it was just a very lucky combination.